Quality-Assurance Information

Changes in Field Methods

The file QA_FLD.TXT
gives a summary of important changes in national network field
methods, constituent coverage, and field sample contamination
from 1973 to 1995 that may affect the use and interpretation of WQN
stream water-quality data.

Changes in Laboratory Methods

The file QA_LAB.TXT
gives a summary of important changes in national network laboratory methods,
reporting conventions, and laboratory sample contamination from 1970 to 1995
that may affect the use and interpretation of WQN stream water-quality data.

Water-Quality Technical Memoranda

A brief summary of the contents of 60 water-quality memoranda
is provided in the file QA_MEMOS.TXT.
These memoranda describe national network protocols and changes in methods, constituent
coverage, and sample contamination that may affect the use and interpretation
of WQN stream water-quality data. Many of these memos are cited in
QA_FLD.TXT and QA_LAB.TXT with Hypertext links.

A chronological listing of the figures
and tables for 7 of the water-quality memoranda, which have
separate graphical files stored in PostScript and GIF format, is provided.
[Hypertext links to these graphics are also provided in the body of
these 7 water-quality memoranda, which can be accessed from the above
files.]

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Last modified: Thu Jan 16 15:21:19 EST 1997